Hello! I'm going to guess that you're trying to open them in Jazz Jackrabbit 2, because I don't associate the Access Violation error message with any level editor software. What version of Jazz Jackrabbit 2 are you using? You can see the version in the bottom left corner of the root menu, the one that shows up after the title screen. If it doesn't say "JJ2+ Beta v5.12" you will need to install JJ2+ 5.12 before Diamondus Ultimate or Jungle Ultimate will work. You can read installation instructions here.